Two different protocols of the Glynne-Lemmerzahl method used for the evaluation of national potato cultivars to Synchytrium endobioticum in Germany (JKI) and Poland (IHAR-PIB) will be compared concerning reproducibility, reliability, efficiency and workload. The final aim is to develop one harmonised European methodology enabling a mutual acknowledgement of the results.

Work package 2 - WP Leader: IHAR-PIBTitle: New differential set of potato cultivars to check identity of potato wart pathotypes

The present differential set (EPPO 2004) used so far by the majority of the EU countries consists of 11 potato cultivars of which only four are registered and commercially available. In Germany, 18 out of 256 registered cultivars (7%) are known to confer resistance not only to pathotype 1 but also to one or more of the pathotypes 2, 6 and 18. These cultivars will be tested in addition to 12 Polish cultivars according to the GL method in order to develop a new differential set of potato cultivars. The final aim is to check the identity of pathotypes/cultures used for resistance testing in different EU countries by applying this new differential set.

The gen Sen1 confers resistance to pathotype 1 and maps on chromosome XI of the potato genome (Hehl et al. 1999). It should be verified whether the Sen1- marker is usable for national variety testing and for selecting breeding lines with resistance to pathotype 1. For achieving this aim the marker should be:

· able to differentiate among susceptible and resistant genotypes,

· diagnostic, i.e. detect Sen1 in all possible genetic backgrounds,

· easy to use (PCR-based) for high-throughput screening.

The final aim is to develop new cultivars resistant to pathotype 1 of potato wart disease by marker-assisted selection